Tractor



FIG. 1 is a perspective view of a tractor showing our new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a rear view thereof.

The broken line showing of the wheels and lower area of the tractor is included for the purpose of illustrating portions of the tractor and forms no part of the claimed design. 

CLAIM The ornamental design for a tractor, as shown and described. 